1. Field of the Invention
The present invention relates to a stereoscopic image pick-up and display system and in particular to a stereoscopic image pick-up and display system which is capable of displaying an appropriate stereoscopic images by changing the stereoscopic degree depending upon the size of a display screen and different stereoscopic image pick-up conditions.
2. Description of the Prior Art
There have heretofore been stereoscopic image pick-up and display systems each comprising a stereoscopic image pick-up device, a stereoscopic image display device which displays the stereoscopic image which has been picked up by the stereoscopic image pick-up device and a medium which are disposed between both devices for transmitting image data and the like.
For example, a stereoscopic image pick-up device which is disclosed in Japanese Published Patent Application JP-A-2001-231055 comprises a image pick-up unit 601 including two CCD cameras 602 and 603 as shown in FIG. 14. Right-eye and left-eye images are picked up by first and second cameras 602, and 603, respectively. At this time, a cross-point (convergence point) CP on the surface of an object (subject) to be picked up S at which optical axes CL1 and CL2 of the first and second cameras 602, and 603, respectively are intersected is formed, so that the stereoscopic images are picked up. A technology has been proposed for determining the distance between the surface of the object and the image pick-up device L (that is, the distance between the pick-up device and CP) based upon the angle of the optical axis and the spacing between two cameras 602 and 603.
Japanese Published Patent Application JP-A-Hei 8-262370 discloses a stereoscopic image display device as shown in FIG. 15, which displays the image which is picked up by the stereoscopic image pick-up device disclosed in the JP-A-2001-231055.
In addition to the stereoscopic display device requiring special glasses, a stereoscopic display device which requires no special glasses and the like has been proposed. In this case, right-eye and left-eye images having a parallax therebetween as stereoscopic information are alternately switched for every image signal (one field) by a liquid crystal device circuit (not shown) and alternate blinking operation of two backlights 705a and 705b is conducted in synchronization with the switched image display on a liquid crystal display unit 704.
When a signal of image for the right-eye is displayed on the liquid crystal display unit 704, one of the backlights 705a is lit in synchronization with an input signal so that light of the backlight is incident upon the right-eye 709a of a viewer (observer). Subsequently, when a signal of the image for the left-eye is displayed on the liquid crystal display unit 704, the other backlight 705b is lit in synchronization with the signal so that light of the backlight is incident upon the left-eye 709b of the viewer. Since one image for right-eye on the liquid crystal display unit can be viewed by only the right-eye of the viewer while one image for left-eye on the liquid crystal display unit can be viewed by only the left-eye of the viewer, both images are merged in the brain of the viewer by the afterimage effect on the retina of the viewer, so that the merged image can be viewed as a stereoscopic image by the three-dimensional perception based upon so-called binocular parallax.
Even when the distance between the pick-up device and CP is measured by the technology of the invention as defined in JP-A-2001-231055 on picking-up the stereoscopic image, the distance between the pick-up device and CP (CP information) is not recorded simultaneously with the stereoscopic image recording. Even if the CP information of the picked-up image is recorded, the CP information is not utilized as a signal for the reference of binocular vision by the technology disclosed in JP-A-Hei 8-262370 when the stereoscopic image is played back.
In particular, when the same content are played back on display devices having different screen sizes, the stereopsis from the screen may vary due to difference in screen size since the amount of the parallax between the right-eye and the left-eye varies, resulting in a problem in that a natural stereoscopic image can not be obtained. Since the stereoscopic image contents for large amusement parks are produced assuming that the display devices have a large size screen on which the contents are displayed, appropriate stereoscopic feeling can not obtained unless the displays have the same screen size. Large size screen provides two strong stereoscopic feeling, making viewers uncomfortable, while small size screen provides less stereoscopic feeling, giving no satisfaction to the viewers.
Since these contents are combinations of various scenes, pick-up conditions, focal-length of the lens of the pick-up unit and the spacing between two pick-up units may not be uniform throughout various contents. If these scenes are simply jointed, different stereoscopic feelings are provided by one content, which provides the viewers with different feeling and physical discomfortability.
Furthermore, the positional relationship between the stereoscopic image pick-up and display device is not necessarily constant and the viewer may not be positioned in the position that is intended by the contents producer. If the viewer is offset from the predetermined viewing position of the stereoscopic display device, he or she is not able to view correct stereoscopic image.
Accordingly, when the stereoscopic video image is produced, the cross-point of the pick-up stereoscopic cameras and the parallax of the computer graphics is adjusted while assuming the size of the display screen on which ultimately the image is displayed. Since the contents which have been produced provide different stereoscopic feeling on the different screens of the stereoscopic image pick-up and display systems, it is necessary to reproduce the stereoscopic video image depending upon the screen size. If the stereoscopic video image is produced by the CG (Computer Graphics), it is necessary to conduct rerendering.
Since there is no way to adjust the parallax which has been determined by the once produced contents when they are played back, the viewer has to adjust the stereoscopic feeling depending upon the distance between the viewing position and the screen.
If the stereoscopic video image is broadcast, there is no way to automatically adjust the stereoscopic feeling of the stereoscopic video image in responsive to an indefinite number of viewers and stereoscopic video image pick-up and display systems having various screen sizes. Therefore, broadcasting of the stereoscopic video images for the indefinite number of viewers is difficult. A technology to adjust the stereoscopic feeling depending upon the screen size is essential for the widespread of the stereoscopic video images.
Therefore, it is an object of the present invention to provide a stereoscopic video image pick-up and display system which is capable of providing the stereoscopic video image having a natural stereopsis even if the video image producing and playback conditions are different.